WO2001063140A1

WO2001063140A1 - Shock absorbing system electronically controlled with cross laws

Info

Publication number: WO2001063140A1
Application number: PCT/ES2001/000071
Authority: WO
Inventors: Juan José MARCOS NUÑEZ
Original assignee: Ap Amortiguadores, S.A.
Priority date: 2000-02-24
Filing date: 2001-02-23
Publication date: 2001-08-30
Also published as: ES2166315B1; ES2166315A1

Abstract

The inside of the spindle actuating the piston of the hydraulic damper is occupied by a rotating control valve (2) that is moved angularly by an electrical motor which is activated by an electronic calculator depending on the state of motion of the vehicle, said spindle and rotating valve having a series of holes that can communicate with one another and the main piston (3) having flow valves (7, 8) enabling or blocking the passage of oil from one cylinder chamber to another. In addition to the main piston (3), two secondary pistons are also provided, a first (14) and a second (21) secondary pistons. The main piston (3) has a double pair of holes (5, 6) that can be cross flown or closed by valves (7, 8) on both faces of said piston. The first secondary piston (14) is associated with holes (9, 10) of the spindle (1) and with holes (29, 31) of the control rod (2). The second secondary piston (21) is also associated with two other holes (27, 28) of the spindle (1) and with holes (30, 32) of the control rod (2). Different number of steps for a given position of the control rod (2) are thus achieved, said steps being controlled by elastic closures based on valves and helicoidal springs that are independent from one another.

Description

ELECTRONICALLY CONTROLLED SHARPENING SYSTEM

WITH CROSSED LAWS OBJECT OF THE INVENTION

The present invention, as expressed in the statement of this specification, consists of an electronically controlled damping system with cross-laws, with which significant advantages over the hydraulic shock absorbers currently used are achieved. Hydraulic shock absorbers, regardless of their type, preferably mounted on motor vehicles, are part of the suspension system in conjunction with the wheels and crossbows or springs.

Shock absorbers are the elements that collect the oscillations of the springs or springs, absorbing them and transforming them into friction. In the case of hydraulic shock absorbers that are the most commonly used in vehicles, their operation is based on the resistance offered by any viscous liquid, such as oil, to pass through a calibrated hole.

Hydraulic shock absorbers are generally made up of a cylinder through which the piston connected to an actuating rod runs, defining two chambers inside: one for expansion or traction and another for compression, both flooded with hydraulic fluid, generally oil as We have indicated above. In the case of bitube dampers there are two concentric tubular walls between which an auxiliary chamber is formed that is partially flooded with oil.

In the movements of the wheels of the vehicle with respect to the chassis, there is an upward and downward movement of said wheels and then the piston driving rod moves in the corresponding direction to compress the fluid inside, both in one way or another.

It is said that the shock absorber works under compression when the wheel axle moves towards the body or chassis, for example as a result of the wheel passing through an obstacle; and to traction or expansion in the opposite case, for example, when the wheel returns to its previous position, or it goes through a depression or bump. A special type of hydraulic dampers incorporates elements that allow a continuous or direct modification of the damping law, through an electronic control system known as variable damping dampers.

Generally the variable damping dampers used in the suspension of vehicles, have functional laws through which if the traction is soft in its operation, its compression operation is also smooth, and on the contrary, if in its operation the traction is hard, also compression is hard. It happens that to improve the comfort of the vehicle, it is important that a hard compression corresponds to a soft and reciprocal compression, for which it is established what is called "cross laws" in the operation of the shock absorber. It is therefore the object of the invention, to establish an electronically controlled damping system, through the use of "cross laws". BACKGROUND OF THE INVENTION Electronic systems based on solenoid valves, motors, etc. are currently known to achieve controlled damping suspensions, according to two modes of use: an automatic one where damping is electronically controlled based on the use of the vehicle, and another tax where the damping remains constantly in sports phase. Driver You can select the operating mode using a switch located on the instrument panel. A warning light on the instrument cluster comes on when the sport mode is selected. In some cases a shock absorber is used with an arrangement such that the piston valve is constituted by a rotating distributor, driven by a small electric motor associated with the piston rod. The electric motor is activated by an electronic calculator depending on the situation and use of the vehicle and allows the distributor to be positioned in different positions: the one corresponding to the sports suspension mode in which oil is not allowed to pass through the distributor, and must be do it through a piston valve, while in the normal suspension and comfortable suspension positions the oil is allowed to pass through the distributor, successively increasing the passage section, which results in a lower stepped damping hardness. The control of the solenoid valves, motors, etc., is entrusted to an electronic calculator that determines the positions that they must take to achieve the different phases of operation and hardening of the damping. The calculator receives the appropriate vehicle speed signals, as well as the activation of the brakes from appropriate sensors, and other signals based on which determines the mode of operation. You can also receive signals of body movements that occur in curves, accelerations and braking, as well as in vertical movements caused by the irregularity of the terrain through which it is circulated, which are sent by conveniently positioned accelerometers.

DESCRIPTION OF THE INVENTION In general, the damping system electronically controlled with cross-laws, which is the object of the invention, takes place through the piston actuation rod itself, where the control rod is axially introduced which is moved by a motor that is also activated by an electronic calculator in function of the situation of the vehicle. The control rod integrally carries a rotary valve that has a series of through holes that, in collaboration with other through holes provided in the rod and those corresponding to the main piston and through valves thereof, allows oil to pass from a chamber to another by the drive rod itself.

Different damping diagrams (force / speed) are obtained that allow a great adaptation to different forms and phases of driving.

It basically comprises the following elements:

- A main piston anchored to the end of the drive rod, forming the expansion and compression chambers, on either side of it. The oil passes from one chamber to another through the holes that pass through it, and so that one or the other is sealed by existing valves on both sides of the piston. - A first secondary piston arranged on one side of the main piston that is related to holes that cross the tubular wall of the rod, these holes being axially separated and being the same capable of communicating with those existing in the rotating control rod driven by the corresponding motor.

- A second secondary piston that is also related to two or more holes in the rod and with the respective control rod. In the operation of the shock absorber, both With compression and traction, several fluid passages can be formed by different paths depending on the number of laws to be achieved. In the constructive form that is recommended, one, two, or three paths can be created for the passage of the fluid. In the case where a single fluid passage is established the traction or compression will be hard, while when there are two of these steps, or all three, the traction or compression will be medium or soft respectively. These simple or multiple steps, are controlled by the electronic calculator to achieve the intended purpose.

Another feature of the present invention is determined by the provision of an elastic membrane, of tubular configuration, disposed between the tubular wall in which the rod is housed and in which both the main piston and the secondary pistons play, and another outer tubular wall envelope. In the annular chamber formed between the elastic membrane and the outer tube, a gas is housed, which facilitates the passage of fluid from the compression chamber to the traction chamber and vice versa, while gas and oil are kept separated by it.

To facilitate the understanding of the characteristics of the invention and as an integral part of this specification, some sheets of drawings are attached in whose figures, for illustrative and non-limiting purposes, the following has been represented:

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1. - It is a partial view in longitudinal section and on one side of the axis of symmetry, of the hydraulic cylinder of an electronically controlled damping system with cross-laws, in accordance with the invention.

Figure 2.- It is a sectional view through a diametral plane of the main piston of the shock absorber. Figure 3.- It is a longitudinal section view. nal and exploded, of the first secondary piston of figure 1.

Figure 4.- It is a sectional view through an exploded diametral plane of the second secondary piston.

Figure 5.- Shows different situations of the main piston and secondary piston bypass valves, with respect to the position of the holes of the rod and control rod. Figures 6a and 6b.- They show how the fluid passage is established so that soft traction-hard compression and soft hard-compression traction take place, respectively, in a shock absorber that mounts the pistons of figures 2, 3 and 4. Figure 7.- It is a partial view in longitudinal section, of the end of the cylinder of the shock absorber, to see the arrangement presented by the elastic membrane located between the two concentric tubular walls.

Figure 8.- It is a partial view of the control rod, showing its tubular end provided with the fluid passage holes.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the numbering adopted in the figures, we can see how the electronically controlled damping system with cross-laws, which the invention proposes, includes the main elements listed below.

1 Vastago

2 Control rod 2nd Solid extension

2b Tubular portion

3 Piston

4 Inner tube

5 Hole 6 Hole 7 valve

8 valve

9 Steps of Stem 1

10 Steps of the rod 1 5 11 Bushing

12 Cap steps 11

13 Valve

14 First secondary piston

15 Axial pitch 10 16 Oblique pitch

17 16 valve

(X) Permanent step

18 Cap

19 Spring 15 20 Valve

21 Second secondary piston

22 Axial pitch

23 Oblique Pass

24 valve

20 (Y) Permanent step

25 Dock

26 Support bushing

27 Steps of Stem 1

28 Steps of Stem 1

25 29 Rod holes 2 related to holes 9 of rod 1

30 Rod holes 2 related to holes 27 of rod 1

31 Rod 2 holes related to 30 holes 10 of rod 1

32 Rod holes 2 related to holes 28 of rod 1

33 outer tube

34 Elastic membrane

35 35 Bushing-first assembly support secondary piston 14

36 Bushing-support for the second secondary piston assembly 21

37 Cap passage 18 38 Camera

With special reference to Figure 1, we can see the situation of the main piston 3 and the secondary pistons 14 and 21, all arranged coaxially to the tubular rod 1. The piston 3 has a seal that is applied against the inner wall of the tube or cylinder 4, thus dividing the inner chamber of the cylinder into two chambers: expansion or traction, and compression.

The axial emptying of the tubular rod 1 is occupied by the control rod 2, which has rotational movement when connected to an electric motor not shown. in the figures, commanded by the electronic calculator. The control rod 2 has a tubular portion 2b provided with holes capable of confronting those existing in the tubular rod, having a solid extension 2a of smaller diameter, the free end of which has a pair of millings for coupling integral with the motor.

In figure 2 we can see the structure of the main piston 3, provided with the holes, in this case oblique 5 and 6 radially distributed, capable of closing on both sides of the piston 3 through valves 7 and 8.

The first secondary piston 14 is mounted inside a support bushing 35 (see figures 1 and 6) and has axial and oblique axial passages 16, which can be closed by means of valves 13 and 17. The valve 13 contacts the plate or thrust bushing 11 provided with a pair of radial holes 12, as shown in Figure 3. In Figure 4 we can see in an exploded way the structure of the second secondary piston 21 and which includes the bushing 18 with radial passages, on which the spring 19 that presses the valve 20 rests. On the other side of the secondary piston 21 itself is the valve 24 assisted by the spring 25 that rests on another plate or support piece 26. References 22 and 23 designate the axial and oblique passages respectively of said second secondary piston 21. For its part, the tubular rod 1 is provided with the holes 9, 10, 27 and 28 normally aligned in the same generatrix and collaborating with the steps 12, 16, 37 and 23, made for this purpose in the bushing 11, piston 14, bushing 18 and second secondary piston 21.

In correspondence with the holes of the tubular rod 1 the control rod 2 has steps 29, 31, 30 and 32. According to the damping laws to be achieved, these steps can be round or torn holes in a circumferential direction. In the figures, the steps 29 and 31 torn in the annular direction are shown and the 30 and 32 are circular holes in two diametral directions, as seen in Figure 8 and in the schematic position of the lower part of Figure 1. As we had indicated at the beginning of this specification, the first secondary piston 14 has permanent passages referenced with "X" (see figure 3) and the second secondary piston 21 is provided with the permanent passages "Y". Figure 5 shows the different respective positions of the holes of the control rod 2 in relation to the holes of the tubular rod 1, thus determining the five combinations shown in the scheme of this figure 5 and corresponding, from above down, by rows, with soft traction hard compression; medium-compression soft traction; soft traction-soft compression; soft medium compression compression; and soft hard compression compression.

To better understand the way in which the oil passages take place, figure 6a shows the paths that the fluid follows, with the control rod 2 in the position shown in figure 1, also coinciding with the upper one of the Figure 5 and defining the case of soft compression-hard compression. Soft traction is caused (figure 6a) as the fluid passes through the holes 6 of the piston 3, the valve 8 opening.

The passage of the fluid through the piston 14 takes place by the permanent passage "X", in addition to the hole 15 of the piston itself and the valve 13 that is open; and through the radial hole 12 of the plate 11; also passing through the hole 9 of the tubular rod 1 and finally through the hole 29 of the control rod 2.

Therefore, a passage of the additional fluid from one chamber to the other through the actuating rod and independently of the passage of the fluid through the piston 3 is verified.

There is a third fluid passage through piston 21, through the permanent "Y" passage; in addition to the axial passage 22 of the piston itself; valve 20 open; passage through the radial holes 37 of the bushing 18; hole 27 of the tubular rod 1; and pass through the holes 30 of the control rod 2.

In short, when the shock absorber works on traction, there are three fluid passages following the paths marked with full-line, dot and line arrows and strokes, conveniently selecting the size of the holes of the rotary valve (tubular portion 2b) so that result in soft traction. Under these conditions, when the shock absorber It works under compression, the flow of fluid takes place through the piston 3 through the holes 5 when the valve 7 is opened, as shown in Figure 6b with a continuous line. The flow of fluid does not take place through the piston 14 since although the control rod 2 has its passage 29 open when it is in communication with the hole 9 of the rod 1, the valve 13 closes the passage through the axial hole 15 of said piston 14; the fluid cannot pass through the oblique hole 16 of the piston 14 because the passage 10 is closed, as seen in the arrangement shown in figure 1 and also in the upper line of figure 5 corresponding to soft traction-hard compression; The fluid can pass through the hole 27 of the rod 1 but the passage 22 is closed because the valve 20 of the piston 21 is prevented; through the hole 28 of the rod 1 can not pass by preventing the control rod 2. Therefore there is only a fluid passage through the piston 3 with the convenient restriction of passage of the valve 7, and the compression is hard.

In figure 6b the three fluid passages are shown with lines of different lines through the main piston and secondary pistons, corresponding to the position of the control rod 2 in which hard compression-hard traction can be performed, also corresponding with the last horizontal line of figure 5.

With special reference now to Figure 7, the hydraulic cylinder of the shock absorber includes, in addition to the tube 4, another outer casing tube 33 and between them the elastic membrane 34 is arranged. A chamber 38 of variable volume in which it is housed is thus determined a gas, such as nitrogen. This variable chamber 38 facilitates the passage of the fluid from the compression chamber to the traction chamber, depending on the position of the rod of actuation, while the membrane 34 keeps the gas and the fluid separated, preventing the gas from entering the traction chamber during the compression phase.

Claims

CLAIMS:

1.- CONTROLLED DAMPING SYSTEM

ELECTRONICALLY WITH CROSSED LAWS, having a hydraulic shock absorber whose actuating rod has a rotary valve internally moved by an electric motor activated by an electronic calculator depending on the situation of the vehicle, this valve having a series of through holes that collaborate with those provided in the rod and valves of the main piston, allowing the passage of oil from one chamber to the other through the rod itself, characterized in that it comprises:

- A main piston (3) with through holes (5, 6), sealed by the valves (7, 8) existing on both sides of the main piston (3),

- A first secondary piston (14) that relates to holes (9, 10) of the rod (1), axially separated and in turn related to the existing ones (29, 31) in the control rod (2), - A second secondary piston (21) also related to two other holes (27, 28) of the rod (1) and other respective (30, 32) of the control rod

(2), all in order that, in the operation of the shock absorber both compression and traction, fluid passages can be formed by different paths depending on the number of laws that are to be achieved, steps that are controlled by the electronic calculator to establish a suitable damping diagram.

2.- CONTROLLED DAMPING SYSTEM

ELECTRONICALLY WITH CROSSED LAWS, according to claim

1, characterized in that the first secondary piston (14) has a plate (11) coaxial to the rod (1), provided with a diametral hole (12) to collaborate with the hole (9) of the rod (1), exerting said pressure saucer (11) on the valve (13) which is capable of closing the axial ducts (15) of said first secondary piston (14), opened laterally on the opposite side to define "X" steps after closing the valve (17 ) arranged on this side of said secondary piston, this valve (17) also sealing the oblique holes (16) thereof to communicate with the holes (10) of the rod

(one).

3.- ELECTRONICALLY CONTROLLED DAMPING SYSTEM WITH CROSSED LAWS, according to claim 1, characterized in that the second secondary piston (21) has a coaxial bushing (18) of the rod, with radial steps that collaborate with the steps (27) established in the rod (1), resting on a wall of this bushing the spring (19) that presses on the valve (20) that is capable of closing the axial ducts (22) that cross said second secondary piston (21), also open laterally in the opposite face to define "Y" steps after closing the valve (24) disposed on this side of said secondary piston (21), this valve (24) also blocking the oblique holes (23) of the second secondary piston (21) , which communicate with the holes (28) of the rod (1), this valve (24) being assisted by a spring (25) that rests on an end plate (26).

4.- CONTROLLED DAMPING SYSTEM

ELECTRONICALLY WITH CROSSED LAWS, according to claim 1, characterized in that the rod (1) and the piston assembly: main (3) and secondary (14, 21) that move in the tubular wall (4) of the hydraulic cylinder, are housed at in turn inside a second tube (33), and there is between them a tubular elastic membrane (34) that conforms to the external tubular wall (33), a deformable chamber (38) filled with a gas that facilitates the passage of the fluid from one chamber to another.